Training Aid

ABSTRACT

A training aid comprises first and second spaced, substantially inextensible, divergent guide lines ( 10, 12 ) lying in a substantially common plane, each substantially inextensible line being fixed at a first end ( 14, 16 ) and tensioned at a second end of elastically deformable tensioning means ( 18, 20 ), a reciprocating element ( 22 ) through opposite ends of which the substantially inextensible lines pass and projectile ( 28 ) attached to the reciprocating element.

The present invention relates to training aids and in particular to training aids for use in practicing the striking of projectiles.

Training aids are known in the prior art for practising the striking of projectiles. Sometimes a projectile (e.g. a tennis ball) is fired from a machine towards a user, which the user then strikes. The machine can store a quantity of projectiles so that it can repeatedly fire them towards the user. The user thereby develops his or her technique by repetitively practising a particular stroke. There are many disadvantages associated with such systems, such as having to retrieve the projectiles after a certain number of “strokes” in order to re-stock the machine, having to provide motive power to operate the machine and having to practice in accordance with the machine's timed operation, rather than when the user is ready.

An alternative means of practising is to repetitively strike a number of projectiles, as is common practice at golf “driving ranges”. However, again the projectiles need to be retrieved and returned to the user—unless an infinite supply of balls is available.

Training aids have therefore been developed that enable a single projectile to be used by automatically returning it to a desired rest position after each stroke. Examples in the prior art include UK patent GB2350568 and international patent application WO 02/41955, both of which relate to projectiles mounted on a reciprocating element that is adapted to slide along a pair of spaced-apart and non-parallel elastic lines. The reciprocating element “pinches” the lines together as it slides along them thereby causing the lines to extend elastically. The stored elastic energy in the lines is used to return the reciprocating element to a desired rest position.

These inventions have a number of drawbacks including, amongst others, problems associated with maintaining consistent line tension.

The present invention aims to provide an improved training aid and method of operation of the same.

A first aspect of the invention provides a training aid comprising first and second spaced-apart, substantially inextensible divergent guide lines but lying in a substantially common plane, each substantially inextensible line being fixed at a first end, and tensioned at a second end by elastically distortable tensioning means, and a reciprocating element, through opposite ends of which, the substantially inextensible lines pass, and to which a projectile is attached.

Thus, striking the object causes the reciprocating element to slide along the substantially inextensible lines and to displace them in their substantially common plane thereby causing the tensioning means to distort and cause a retarding force to be imparted to the reciprocating element by the tension in the substantially inextensible lines, the tension being such that it imparts a retarding force to the reciprocating element to urge it to return towards or to a rest position at or near the fixed ends of the guide lines.

A second aspect of the invention provides a method of urging a struck object to return to a rest position, the object being connected to a reciprocating element through ends of which a pair of substantially co-planar, spaced apart divergent substantially inextensible guide lines pass, the substantially inextensible lines being biased in the substantially common plane of the lines by distortable tensioning means such that moving the reciprocating element in the direction of the lines causes the lines to be pinched together or parted and the distortable tensioning means to impart a bias to the lines in the opposite sense to the pinching or parting action, wherein the imparted bias causes the reciprocating element to be urged in the opposite direction in which it was struck.

A third aspect of the invention provides a training aid capable of urging a projectile towards or to return to a rest position after having been struck and restraining means for inhibiting the rebound of the projectile away from the rest position, wherein the restraining means comprises means for dissipating energy from the projectile as it moves into the vicinity of the rest position as it is urged towards or returned thereto.

The projectile of the invention may be of any type, although it is envisaged that a ball, for example, but without limitation to, a golf ball may be provided.

The lines can be fixed at one end using a hook and eye arrangement or a pulley for easy connection and disconnection. The hook and eye arrangement, where provided, may comprise a snap hook and/or a loop formed in the line using a swaged ferrule.

The elastically distortable tensioning means, may be of any suitable type, such as a spring or a resiliently deformable member. The tension in the elastically distortable tensioning means is preferably adjustable by the user.

The tensioning means may accordingly, comprise a spring to which the line or lines are connected. A pulley may be provided to connect the line or lines to the spring to reduce friction therebetween. The tension in the spring may be adjustable by the provision of a pre-tensioner in the form of a screw-threaded connection or a rack connection that can be extended or shortened to increase the tension in the spring. The spring may be interchangeable with springs of differing Hooke constants. Additionally or alternatively, the spring may be pre-compressible by the insertion of spacers between the spring and an abutment surface therefor.

Where the elastically distortable tensioning means comprises a resiliently deformable member, which, where provided, may comprise a length of elasticated cord or a resilient support member. Where a resilient support member is provided, it may comprise one or more flexible rods, to which the lines are connected. The rod may be manufactured of any resilient material, although spring steel or carbon/glass fibre reinforced polymers are envisaged as suitable materials. The angle of the rod or rods, where provided may be adjustable to pre-tension the lines to a desired tension.

The reciprocating element preferably has spaced-apart connection means, e.g. apertures, hooks or other formations, to which the substantially inextensible lines are slidably connected. Preferably, the connection means are located substantially at opposite ends of the reciprocating element. The rest position preferably corresponds to a position whereby the separation of the substantially inextensible lines substantially corresponds with the spacing of the spaced apart connection means.

The reciprocating element may comprise a substantially inextensible bar or tube (e.g. a plastics or steel tube) preferably having apertures at either end thereof through which the substantially inextensible lines are threaded.

In a preferred embodiment of the invention, the reciprocating element comprises a pair of connectors through which each of the substantially inextensible lines pass. The reciprocating element may be a length of cord. The connectors, where provided, may be swivels to accommodate twisting of the cord. The cord is preferably relatively inextensible, although a slight elasticity is desirable for shock absorbing purposes. In a most preferred embodiment, the cord, where provided is manufactured of a polyurethane or other similar material.

The projectile, e.g. a golf ball, is connected to the reciprocating element, either by having an aperture therein through which the reciprocating element passes or being tethered thereto by a tethering cord. Where the former method of connection is employed, the projectile may be slidable along the reciprocating element, although it is preferred that the projectile is fixed.

A support frame may be provided for maintaining the substantially inextensible lines in a desired relationship to one another and the user. The support frame may comprise a U-shaped member and a leg extending therefrom. The support frame, where provided, may be adapted for securement to a surface. The support frame may be anchorable into soft ground (e.g. grass) using one or more spikes (e.g. tent pegs) driven through apertures provided in the support frame into the soft ground. Additionally or alternatively, the support frame may be glued, nailed, bolted, riveted screwed or otherwise mechanically secured to a surface.

The substantially inextensible lines may be anchored into a tee plate. The tee plate may be connected to a footplate on which the user stands. The tee and footplates may also be anchorable or securable to a surface. The footplate, where provided, may have an interchangeable surface thereon, which can be interchanged to suit the requirements of the user. The interchangeable surface may comprise a piece of natural turf or man-made grass to simulate a fairway. Alternatively, a rubber mat, sand, dirt, wood or a water-filled tray, etc., may be provided to simulate other conditions.

A restraining means may be provided to prevent or inhibit recoil of the reciprocating element away from the desired rest position after each stroke. The restraining means may comprise a resilient flap adapted to interfere with, and hence dissipate kinetic energy from the reciprocating element and/or projectile.

Alternatively, the restraining means may comprise a magnet adapted to attract a metallic reciprocating element.

The “optimal” rest position of the reciprocating element may be adjustable by adjusting the position of the restraining means to suit the user.

A slidable element may be provided on one or more of the substantially inextensible lines to indicate the furthest extent of travel of the reciprocating element during use. A scale may be provided (e.g. graduations on one or more of the lines) to provide an indication of the equivalent distance a “free” projectile would have travelled given the same impact. The scale, may provide an indication of an equivalent driving yardage.

For practice apparatus of the type having a spaced apart divergent guide lines lying in a substantially common plane, each line being fixed at a first end and tensioned at a second end, and a reciprocating element slidable along the lines and to which a projectile is attached, it may be useful to be able to monitor how the projectile has been struck. In particular it may be useful to know whether the projectile has been struck straight or to either side. It may also be useful to know the strength with which the projectile has been struck and possibly to be able to evaluate the distance it would have travelled, if not restrained by its attachment to the reciprocating element.

Accordingly another aspect of the invention provides a training aid comprising a pair of spaced, non-parallel guide lines but lying in common plane, a reciprocating element slidable along the lines and carrying a projectile, wherein striking the projectile urges the reciprocating element along the lines draws the lines towards each other to generate a returning force to return the reciprocating element to its start position, characterized by means for monitoring direction and/or power of the strike on the projectile.

The means for monitoring direction and/or power may comprise means for measuring the extent and/or direction of movement of an apparatus component acted upon by deviation of a guide line.

The means for monitoring the direction of a struck projectile relative to a desired direction may be provided by having the guide lines connected to pivotable members, so that if the projectile is struck to one side of the desired direction line the guide lines and hence the pivotable members will be seen to move to one side or the other.

The apparatus component may be a pulley or a combination of pulleys rotatable as a result of deviation of the guide lines. Ends of the guide lines may extend round a pulley or may be linked to a line round a pulley. The pulley may be fixed or may be movable but contained to return to a rest position, such as by spring means or the like. The or each pulley may be provided with an encoder to provide a signal indicative of the extent and/or direction of movement of the pulley. The encoder may provide an indication of rotational movement or linear movement of the pulley.

The apparatus of this aspect of the invention preferably also includes display means for showing the results from the encoders. The results from the encoders are preferably associated with means for calibrating the results. Thus, for example, using the apparatus for practising golf it may be possible to ascertain deviation and the direction of deviation of a golf shot from a desired direction and possibly also the distance the golf ball would have travelled under normal conditions.

The apparatus of this aspect of the invention may also be an apparatus according to any of the previous aspects of the invention.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which;

FIG. 1 shows a schematic representation of the principle of operation of the invention;

FIGS. 2 and 2 a show a perspective view of a first version of the invention adapted as a golf swing training aid;

FIGS. 3 and 3 a show a perspective view of an alternative embodiment of the invention;

FIGS. 4 and 4 a show a perspective view of a further alternative embodiment of the invention;

FIG. 5 shows side and elevations of a detail of a restraining means;

FIG. 6 shows a cross section through an alternative restraining means;

FIG. 7 shows a further alternative restraining means;

FIG. 8 shows a preferred embodiment of the reciprocating element;

FIG. 9 shows a further alternative embodiment of the invention;

FIGS. 10 and, 11 show yet a further embodiment of the invention intended to show sideways deviation of a struck projectile;

FIGS. 12 and 13 show another embodiment to show sideways deviation of a struck projectile; and

FIGS. 14 and 15 show another embodiment of the invention having means for monitoring direction and power of a strike on a projectile.

Turning now to FIG. 1 of the drawings, the invention comprises first and second spaced-apart, substantially inextensible lines 10 & 12 having a non-parallel relationship but lying in a substantially common plane. Each substantially inextensible line 10 & 12 is fixed at a first end 14 & 16, and tensioned at a second end by elastically distortable tensioning means 18 & 20. A reciprocating element 22 through opposite ends of which 24 & 26, the substantially inextensible lines 10 & 12 pass is provided. A projectile 28 is attached to the reciprocating element 22. The first and second substantially inextensible lines 10 & 12 can be separate lines, but in the present example, they are formed of a continuous substantially inextensible line looped around a pulley 30. This arrangement ensures that the tension in each line 10 & 12 is substantially equal.

The upper part of FIG. 1 shows the reciprocating element 22 in a rest position. When the projectile 28 is struck in the direction indicated by arrow P, the reciprocating element 22 travels along the lines 10 & 12. The reciprocating element is substantially inextensible or extensible only to a relatively minor extent, which draws the lines 10 & 12 inwards as indicated by arrows Q & R.

Because the lines 10 & 12 are substantially inextensible, the length of line ABDE must be the same as line FGIJ. However, “pinching” the lines 10 & 12, as indicated by arrows Q & R, causes the effective length of line FGI to be greater than ABD. To compensate for this, the distortable tensioning means 18 & 20 distort (i.e. extend) from length CD to length HI.

Kinetic energy imparted to the projectile 28 upon striking is dissipated as potential energy in distorting the distortable tensioning means 18 & 20. The potential energy stored in the distortable tensioning means 18 & 20 is then released back into the lines 10 & 12 when the reciprocating element 22 comes to rest, thereby reversing the “pinching” forces Q & R. The reciprocating element 22 is thus driven back towards a rest position, in the opposite direction to arrow P enabling the cycle to be repeated.

FIG. 2 shows a possible physical embodiment of the invention comprising first and second substantially inextensible lines 10 & 12, formed by anchoring ends 14 & 16 of a continuous line about a pulley 30. The lines 10 & 12 are tensioned using distortable tensioning means 18 & 20 in the form of pulleys affixed to tension springs. The end pulley 30 and distortable tensioning means 18 & 20 are connected to a support frame 32 comprising a relatively rigid U-shaped member 34 and a leg 36 extending therefrom. The ends 38 of the support frame 32 are adapted to be anchored into soft ground (e.g. grass) using a spike (e.g. a tent peg) driven through an apertured base plate (not shown for clarity).

The lines 10 & 12 are anchored 14 & 16 into a tee plate 40. The tee plate is connected to a footplate 42 on which the user (not shown) stands. The tee and footplates 40 & 42 are also anchored 44 into soft ground using spikes (e.g. tent pegs) driven through apertures therein (not shown for clarity). The footplate 42 has an interchangeable surface 46 thereon, which can be interchanged to suit the requirements of the user. For example, a piece of turf or man-made grass could be used to simulate a fairway or a rubber mat may be used to simulate a tee. Other surfaces 46 could also be used, e.g. sand, dirt, wood, a water-filled tray, etc., to simulate whatever conditions the user desires.

FIG. 2 a shows a detail of the tensioning means 20 comprising a spring 21 connected to a pulley 23 around which the line 12 passes. A threaded bar 25 passes through an aperture in the support frame 34 and a knob 27 is provided to adjust the position of the pulley 23 relative to the support frame 34.

FIG. 3 shows an alternative embodiment of the invention having separate lines 10 & 12 that are connected to resiliently deformable tensioning means provided by levers 48 & 50 pivotally mounted on a support frame 52. The levers 48 & 50 are relatively free to move about pivots 54 & 56. A tension is applied between the ends of the levers 48 & 50 by a spring 58 connected therebetween. Thus, in use, the lines 10 & 12 are pinched causing the levers 48 & 50 to move inwards in the direction indicated by arrows S & T. The resultant opposite outwardly directed force, indicated by arrows U & V is resisted by the spring 58. A slidable element 13 is also provided to indicate the furthest extent of the reciprocating element 22. The substantially inextensible lines 10 & 12 have markings (not shown) thereon to provide a scale, against which a “driving yardage” can be estimated.

The frame 52 is manufactured of box-section metal (e.g. steel) and is adapted for permanent (but removable) installation by way of bolts 60 tapped into the floor. The apparatus can thereby be installed, e.g. in an indoor driving range. The provision of an interchangeable surface 46 can add to the realism of the apparatus, (especially where a section of real turf is used on an indoor located apparatus).

FIG. 3 a shows a rack assembly 51 comprising rack members 53 connected to the levers 48 & 50. A spring 58 is provided having bent ends 55 that are insertable into apertures 57 in the rack members 53. Positioning the ends of the spring 55 in different apertures 57 causes the tension transmitted by the spring 58 to the levers 48 & 50 to be adjustable.

FIG. 4 is similar to FIGS. 2 and 3, except that the distortable tensioning means comprises a pair of flexible rods 62 & 64 rigidly mounted on a support frame 66. The rods 62 & 64 may themselves be flexible (e.g. manufactured of a resiliently deformable material such as spring steel or polymer reinforced carbon fibre) or they may be relatively rigid, but mounted on springs 68 & 70 as in the illustrated example. Again, the support frame 66 is bolted to the floor using bolts 60.

FIG. 4 a shows how the flexible rods 62 are pivotable about a pivot 61 on the support frame 66. A triangulation member 63 is provided to lock the rod 62 at a desired angle. An end of the triangulation member 63 is insertable in various apertures 65 in the support frame 66 to adjust the angle of the rod 62 and hence the tension in the lines 10 & 12.

FIG. 5 shows an optional restraining means in the form of a resilient flap 70 mounted on the tee plate 40. The flap 70 has a bifurcated end 72 that is arranged to accommodate one or more of the lines 10 or 12. The flap 70 is quite flexible, enabling the reciprocating element 22 to bend it forwards as indicated by arrow W when the object is struck. When the reciprocating element 22 returns after travelling forward and back, it has sufficient energy to deform the flap 70 in the direction indicated by arrow X, to pass thereby but in doing so, dissipates too much energy to re-pass the flap 70 (arrow W) on the rebound. The flap 70 thereby prevents the reciprocating element 22 from rebounding on the return path leaving it in a desired position to be re-struck by the user without the user having to alter his stance.

FIG. 6 shows an alternative optional restraining means comprising a ferrule 74 clamped to a line 10 using a grub screw 76. The ferrule comprises a magnet 78 that is adapted to attract a metallic reciprocating element 22. The magnet 78 has a curved and padded surface 80 for optimal engagement with the reciprocating element. The “optimal” rest position of the reciprocating element 22 can be adjusted to suit the user by sliding the ferrule along the line (arrow Y) and re-clamping with the grub screw. The strength of the magnet is selected such that it has a minimal effect on the movement of the reciprocating element 22 when in use, but prevents the reciprocating element 22 from “rebounding” after each cycle.

FIG. 7 shows a further alternative restraining means comprising a resiliently deformable horn 79 arranged adjacent to one or more of the lines 10 & 12. The tee plate 40 has a rubber mat 81 thereon such that when the reciprocating element 22 returns to a rest position, it becomes wedged either by the horn 79, or between the horn 79 and the rubber mat 81. This arrangement reduces the likelihood of the reciprocating element 22 rebounding from the rest position.

FIG. 8 shows a preferred embodiment of the reciprocating element 22, which comprises a pair of swivels 43 through which each of the substantially inextensible lines 10 & 12 passes. A length of polyurethane cord 45 is attached at opposite ends to the respective swivels 43. The projectile 28 has a bore therethrough, through which the cord 45 is passed.

FIG. 9 shows a further alternative embodiment of the invention whereby the elastically distortable tensioning means 18 comprises a resilient beam 82. The beam 82 is generally arcuate, being either manufactured that way or pre-flexed during use, and the inextensible lines 10 & 12 are fixed to extreme ends thereof. The resilient beam 82 is affixed at its midpoint to a support frame 52 as previously described.

The resilient beam 82 is arranged to flex to accommodate the effective length change of the inextensible lines 10 & 12 as the reciprocating element 22 slides therealong. It is envisaged that the resilient beam 82 could be manufactured of any suitable resilient material, although plastics (for example, but without limitation to fibre reinforced polymer) or metals (for example, but without limitation to spring steel) may be preferred.

In FIGS. 10 and 11 of the accompanying drawings, a training aid has first and second spaced, substantially inextensible lines 100 and 102 having a non-parallel relationship lie in a common plane. Each line 100 and 102 is fixed at a first end 104 and 106 where the lines are closer together and at the other end to pivot points A and B respectively that are maintained at a constant separation by a bar 103. The pivot points A and B are respectively connected by rods 105 and 107 to pivot points A¹ and B¹ on a support 109.

Slidable along the lines is a relatively inextensible reciprocating element 108 to which is attached a golf ball 110, although it could be some other projectile.

As in previously described embodiments, when the golf ball in the vicinity of the first fixed ends is struck in practising a golf shot, the golf ball and the reciprocating element are driven towards the other ends of the lines 100, 102. Because the reciprocating element is relatively inextensible, the lines are drawn together and this generates a force to return the reciprocating element towards the first fixed ends of the lines 100, 102.

Additionally, as the pivot points A and B are at a constant separation any deviation in the flight of the projectile from a straight line midway between the lines 100, 102 will cause the lines to deviate to one side or the other and hence the 105 and 107 will pivot A¹ and B¹, which will show the direction of deviation. As shown in FIG. 10 the golf ball has been hit to the left and in FIG. 11 the golf ball has been hit to the right.

FIGS. 12 and 13 show a deviation monitoring arrangement for a training apparatus having a pair of divergent guide lines slidingly carrying a relatively inextensible reciprocating element between them. The guide lines diverge from a start position. A projectile to be struck is attached to the reciprocating element. The guide lines are resiliently extensible, so that when the projectile is struck the reciprocating element is driven along the guide lines drawing them towards each other to generate a returning force to return the reciprocating element towards its start position.

To monitor whether the path of travel of the struck projectile is straight or deviates to me side or the other, the ends of the guide lines remote from the start position are attached to corners A and B of a triangular frame 112. The triangular frame is pivotally mounted at its other corner at 114. The frame has an extension 116 from its pivot point connected to a spring 118.

If the projectile is struck off line, such as with a hook or a slice, the reciprocating element will tend to pull the guide lines to one side or the other. This will cause the triangular frame 112 to move to one side or the other about the pivot point 114. The pivot point can be provided with an encoder to detect the direction of deviation of the projectile (golf ball) from a desired direction of travel and the extent of such deviation. The results from the encoder may be displayed on suitable display means and with calibration can provide a realistic indication of the travel of the projectile. The spring 118 serves to urge the framework and hence the guide lines back to their start position and also provides resistance to the deviation of the guide lines as the reciprocating member travels along them after striking of the golf ball.

Turning to FIGS. 14 and 15 there is shown a monitoring arrangement for a practice apparatus 200 which has its two lines 202 and 204 connected at their upper ends at X and Y to bars 206 and 208 respectively. The bars 206 and 208 are pivotally mounted on a support bar 210 and have their other ends X′ and Y′ connected to opposite ends of a wire or the like 212. The wire 212 runs from each end over fixed pulleys A and B and under a movable pulley C. The movable pulley C is connected by a spring 214 to a base.

The lines 202 and 204 carry the usual reciprocating element in sliding fashion, the element having a ball attached thereto as shown in earlier described embodiments. When the ball is struck the reciprocating element moves along the lines drawing them together, which pivots the bars 206 and 208 pulling their respective ends X and Y towards each other. Their opposite ends Z′ and Y′ consequently move apart and the ends of the wire 212 move oppositely pulling the movable pulley C towards the fixed pulleys against the action of the spring 214.

The pulleys A and B are provided with rotary encoders and suitable electrical circuitry to provide indications of their extents of rotation. Addition of the rotational movement of the pulleys A and B provides an indicating of the power of the strike on the ball and subtraction of the rotational movement of the pulleys A and B will indicate the direction and degree of deviation of movement of the ball from a straight line path between the guide lines. The power and direction information may be displayed on a suitable device and the device calibrated in order to provide realistic distance and deviation information.

Alternatively, the pulley C may be provided with both linear and rotational encoders. The linear encoder will measure the distance the pulley moves when the ball is struck and that will give an indication of power of the stroke. By calibration the power indication may be turned into a realistic distance of travel assuming that the ball had been struck without encumbrance of the apparatus itself.

The rotational encoder can provide an indication of whether there has been any sideways deviation imparted to the ball on being struck as well as the extent of such deviation. 

1. A training aid comprising first and second spaced, substantially inextensible divergent guide lines lying in a substantially common plane, each substantially inextensible line being fixed at a first end and tensioned at a second end by elastically deformable tensioning means, a reciprocating element through opposite ends of which the substantially inextensible lines pass and a projectile attached to the reciprocating element.
 2. A training aid as claimed in claim 1, wherein the inextensible lines are tensioned such that when the reciprocating element moves away from the fixed ends thereof on striking off the projectile, the lines exert a retarding force on the reciprocating element and then a returning force.
 3. A training aid as claimed in claim 2, having restraining means for inhibiting rebound of the projectile away from a rest position.
 4. A training aid as claimed in claim 3, wherein the restraining means for dissipating energy from the projectile as its moves into the vicinity of the rest position.
 5. (canceled)
 6. A training aid as claimed in claim 5 claim 1, wherein the projectile is a golf ball.
 7. A training aid as claimed in claim 1, wherein the lines are fixed at one end using a hook and eye arrangement.
 8. A training aid as claimed in claim 1, wherein the lines are fixed at one end using a pulley arrangement.
 9. A training aid as claimed in claim 1, wherein the elastically deformable tensioning means comprises a spring.
 10. (canceled)
 11. A training aid as claimed in claim 1, wherein the tension is in the elastically deformable tensioning means is adjustable.
 12. A training aid as claimed in claim 1, wherein the guide lines are connected to the elastically deformable tensioning means via pulleys.
 13. (canceled)
 14. A training aid as claimed in claim 13, wherein the resilient support member comprises one of more flexible rods made of a selected one of spring steel or carbon/glass fibre reinforced plastics.
 15. (canceled)
 16. A training aid as claimed in claim 14, wherein the angle of the or each rod is adjustable to pretension the guide lines.
 17. A training aid as claimed in claim 1, wherein the reciprocating element comprises a substantially inextensible bar or tube having an aperture at each end, through which a guide line passes.
 18. (canceled)
 19. A training aid as claimed in claim 1, wherein the reciprocating element is a length of cord.
 20. A training aid as claimed in claim 1 including a support frame for maintaining the inextensible lines in a desired relationship to one another and the user.
 21. A training aid as claimed in claim 20, wherein the support fame comprises a u-shaped member and a leg extending therefrom.
 22. A training aid as claimed in claim 1, wherein the guide line are anchored to a tee plate connected to a foot plate.
 23. (canceled)
 24. A training aid as claimed in claim 4, wherein the restraining means comprises a resilient flap adapted to interfere with the projectile.
 25. A training aid as claimed in claim 4, wherein the restraining means comprises a magnet adapted to attract a metallic reciprocating element.
 26. A training aid as claimed in claim 1 having slidable element on one or both of the guide lines to indicate extent of travel of the reciprocating element.
 27. A training aid capable of urging a projectile attached to a reciprocating element on a pair of guide lines towards or to return to a rest position after having been struck and restraining means for inhibiting rebound of the projectile away from the rest position, wherein the restraining means comprises means for dissipating energy from the projectile as it moves into the vicinity of the rest position.
 28. A training aid as claimed in claim 27 having means for monitoring at least one of direction and/or and power of a strike on the projectile.
 29. A training aid comprising a pair of spaced, divergent guide lines in a common plane, a reciprocating element slidable along the lines and carrying a projectile, wherein striking the projectile urges the reciprocating element along the lines draws the lines towards each other to generate a returning force to return the reciprocating element to its start position.
 30. A training aid as claimed in claim 28, wherein the means for monitoring at least one of direction and/or and power comprises means for measuring at least one of extent and direction of movement of a component of the training aid acted upon by deviation of a guide line.
 31. A training aid as claimed in claim 30, wherein said component is a pivotable member.
 32. (canceled)
 33. (canceled) 